The present invention is related to an apparatus and method for reducing a hazardous gas content of an effluent from a process chamber.
Fluorocarbon, chlorofluorocarbons, hydrocarbon, and other fluorine containing gases are used in, or formed as a byproduct during, the manufacture of integrated circuits in process chambers. These gases are toxic to humans and hazardous to the environment. In addition, they may also strongly absorb infrared radiation and have high global warming potentials. Especially notorious are persistent fluorinated compounds or perfluorocompounds (PFCs) which are long-lived, chemically stable compounds that have lifetimes often exceeding thousands of years. Some examples of PFCs are carbon tetrafluoride (CF4), hexafluoroethane (C2F6), octafluorocyclopropane or perfluorocyclobutane (C4F8), difluoromethane (CH2F2), hexafluorobutadiene or perfluorocyclobutane (C4F6), perfluoropropane (C3F8), trifluoromethane (CHF3), sulfur hexafluoride (SF6), nitrogen trifluoride (NF3), and the like. For example, CF4 has a lifetime in the environment of about 50,000 years and can contribute to global warming for up to 6.5 million years. Thus it is desirable to have an apparatus or method that can reduce the hazardous gas content of effluents, and especially PFCs, that may be released from process chambers.
Perfluorocompounds are utilized in numerous semiconductor fabrication processes. For example, perfluorocompounds are used in the etching of layers on substrates, such as oxide, metal and dielectric layers. Perfluorocompounds can also be used during chemical vapor deposition processes. Additionally, process chambers can be cleaned of etch or deposition residue using perfluorocompounds. These hazardous compounds are either introduced into a process chamber or are formed as byproducts within the process chamber and may be exhausted from the chamber in an effluent gas stream.
Thus, it is desirable to minimize the introduction of such harmful gases and byproducts into the environment. There is also a need to minimize the harmful content of the effluent gas released into the atmosphere in an efficient and inexpensive manner. There is a further need to reduce PFC and other harmful gases to the lowest possible levels, preferably by at least about 95%, especially for industries which widely use PFCs, even though such use is a relatively small component of the overall consumption or release of PFCs in the world.
The present invention is useful for reducing a content of hazardous gases, such as PFCs, in an effluent gas, such as an effluent that results from processing of substrates, for example semiconductor wafers and other electronic devices. By hazardous gas it is meant any toxic, harmful or undesirable gas, including but not limited to PFCs, chlorofluorocarbons (CFCs), hydrocarbons, other fluorine containing gases, and other undesirable gases.
In one aspect of the invention, a gas energizing apparatus comprises a reactor adapted to receive gas, the reactor comprising an inner surface comprising a fluorine-containing compound. The apparatus also comprises a gas energizer to energize the gas in the reactor.
In another aspect of the invention, a gas treatment apparatus capable of treating an effluent gas from a process chamber comprises a reactor adapted to receive the effluent gas, the reactor comprising an inner surface comprising a fluorine-containing compound, and a gas energizer to energize the effluent in the reactor to treat the effluent gas.
In another aspect of the invention, a method of energizing a gas comprises providing an inner surface comprising a fluorine-containing compound in a reactor, introducing gas into the reactor, and energizing the gas in the reactor.
In another aspect of the invention, a method of treating an effluent gas from a chamber comprises performing a process in a process chamber to generate an effluent gas, providing an inner surface comprising a fluorine-containing compound in a reactor, introducing the effluent gas into the reactor, and energizing the effluent gas in the reactor to treat the effluent gas.
In another aspect of the invention, a gas energizing apparatus comprises a reactor adapted to receive gas, the reactor comprising an inner surface comprising a material comprising an oxide and a thermal transformation stabilizing agent and a gas energizer adapted to energize the gas in the reactor.
In another aspect of the invention, a method of energizing a gas comprises providing an inner surface comprising a material comprising an oxide and a thermal transformation stabilizing agent in a reactor, introducing gas into the reactor, and energizing the gas in the reactor.